狂想的窝牛.技术.NET.Dropdownlist

用递归在Dropdownlist中显示树状结构(连数据库)

protected void Page_Load(object sender, EventArgs e)
         {
             Class.sqlconn.Open();
           
             SqlDataAdapter da = new SqlDataAdapter("select so_id,so_name,so_parentid from en_sort order by so_order asc", Class.sqlconn);
             DataTable dt = new DataTable();
             da.Fill(dt);
             Class.sqlconn.Close();
             BindData(dt, 0,"");

         }

         private void BindData(DataTable dt, int id,string blank)
         {
             DataView dv = new DataView(dt);
             dv.RowFilter = "so_parentid = " + id.ToString();

             if (id != 0)
             {
                 blank += "|─";
             }
             foreach (DataRowView drv in dv)
             {
             
                 ListItem li = new ListItem();
                 li.Text = blank + drv["so_name"].ToString();
                 li.Value = drv["so_id"].ToString();
                 this.DropDownList1.Items.Add(li);
                 BindData(dt, Convert.ToInt32(drv["so_id"]),blank);
             }
         }